Possible GammaSteel C2 Using Spoofed iPhone User Agent

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1071.001Web Protocols
- T1102.001Dead Drop Resolver
Exfiltration
Impact

What it detects

This rule detects outbound web traffic presenting an iPhone OS 18_0 user agent from an endpoint. Gamaredon GammaSteel beacons to its command server with this mobile user agent to blend in with normal traffic. Mobile browser user agents originating from a Windows workstation proxy are anomalous and merit review.

Reporting behind it

Related detections9 linkedT1071.001 — drag to rearrange

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Possible GammaSteel C2 Using Spoofed iPhone User Agent

Pivot detection · T1071.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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